Katharine Hepburn once remarked that the secret to Fred Astaire and Ginger Rogers' success was that he gave her class while she gave him sex appeal. Hepburn's equation helps explain the long and awkward tango between Hollywood and Washington. To Washington, Hollywood offered glamour; to Hollywood, Washington provided substance, or at least the illusion of it.

The two cities are the source of much American mythology. Washington promulgated the fable that any boy -- or girl -- could grow up to be President; Hollywood invented the fantasy that the...